3D scanning

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3D scanning is the process of making a 3D file from a statue, model, or building.

Structured-light scanning

Structured-light scanning is making a 3D file of an object just using a camera or a camcorder with either 1) a projected grid from a video projector or 2) a projected line(s) from low power laser light source (generally, a laser-pointer or similar). It should be born in mind that 3D scanning produces clouds of discrete points, not contiguous surfaces. A scanned primitive shape like a cube or a sphere is not recognised by CAD programs, and point cloud processing software is often the most expensive component of commercial systems.

DIY

SplineScan is free and open source software. It has reached a high level of polish and sophistication. The website and documentation does not yet reflect this. See also the RepRap local documentation stub SplineScan.

David Laserscanner is closed source but there is a *free* basic scanning software version, and a commercial edition that costs €199, for which you get additional tools for assembling and combining multiple scans of the same object into a watertight model, and for applying textures. David requires a 3-plane "corner" with calibration targets, a laser line generator, red or green, and a web cam or a video recording of the line being swept over the target in the "corner". There's also a "for sale" starter kit. The kit costs €400 and you need a Windows computer. You get a suitable camera and laser line, and the panels to build and calibrate the "corner". They've spent a lot of time on their website, and there's good feedback and advice from users and the vendors through good forums, and many real-world user examples. If you already have a laser line generator, and a web or video camera, and three 600mm x 600mm sheets of MDF or similar, you can build a David scanner and be operating it within a couple of hours. Scan output is .obj, and if you're using the free version, Meshlab can assemble and stitch multiple scans into one object.

Commercial

There are probably a number of expensive solutions for doing this, based on good software, a camera, and a laser pointer. And good marketing.

Photogrammetry scanning

This is making a 3D file of an object just using a camera, or a camcorder, even without a laser-pointer-like light source.

Technically this is called 'photogrammetry' or more precisely 'object reconstruction': http://en.wikipedia.org/wiki/Photogrammetry

Touch-probe scanning

Main page: CMM
  • "Robot Arm Type": here a human guides a 'finger' of a device that looks like a robot arm over a model or sculpture. This deals well with overhangs and precise geometries like boreholes or outer diameters.
  • "Generic Touch Probe": we can mount a touch probe toolhead on a 2+1 axis machine like a CNC router, mill, or RepRap. This is convenient if we don't have a robot arm handy.

Further reading

See also David_Project.